Usually low Thyroid . Post ablative hypothyroidism is a condition where the thyroid gland is not functioning well and thus the patient needs more thyroid hormone. A "high tsh" actually mean there is not enough thyroid in the blood, thus an increase in dosage of the synthroid (thyroxine) is needed. Go see your family doctor and he/she will make adjustments and recheck the TSH level. This is very sensitive to thyroid in the body.